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Amabili M, Franchini G, Garziera R. Experimental characterization of residual deformations in human descending thoracic aortas. J Mech Behav Biomed Mater 2024; 153:106492. [PMID: 38479211 DOI: 10.1016/j.jmbbm.2024.106492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/18/2024] [Accepted: 03/01/2024] [Indexed: 03/26/2024]
Abstract
The effect of residual stresses on the deformation of human aortas under pulsatile pressure is relevant. Experimental measurements of residual deformations are necessary to characterize residual stresses in human aortas. For this reason, an experimental study is carried out. In the present study, longitudinal and circumferential strips from descending thoracic aortas obtained from 21 donors, harvested during organ donation explant, underwent residual deformation measurements. The intact wall and the three separated layers were tested in both directions, resulting in 8 tests per donor, which gives a relevant set of experimental data for further studies. Results show significant residual deformations both in circumferential and longitudinal directions, which are compatible with a significantly compressed intima in the unloaded aorta. In particular, the measured mean effective curvature was -0.193 ± 0.064 (1/mm) for the circumferential strips and -0.076 ± 0.030 (1/mm) for longitudinal strips of the full wall. The effects of age and gender were also investigated.
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Affiliation(s)
- Marco Amabili
- School of Engineering, Westlake University, Hangzhou, Zhejiang province, PR China; Department of Mechanical Engineering, McGill University, Montreal, Canada.
| | - Giulio Franchini
- Advanced Material Research Center, Technology Innovation Institute, Abu Dhabi, United Arab Emirates
| | - Rinaldo Garziera
- Dipartimento di Ingegneria ed Architettura, University of Parma, Parma, Italy
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2
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Zhu X, Wang X, Wu H. Calculation method and analysis of residual stress in the strip bending roller straightening process. Sci Rep 2024; 14:9149. [PMID: 38644401 PMCID: PMC11033262 DOI: 10.1038/s41598-024-59305-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Accepted: 04/09/2024] [Indexed: 04/23/2024] Open
Abstract
Taking thin gauge strip as an example, the deformation process of metal strip in bending roll straightening was studied. Based on the theory of discrete, curvature integral and elastic-plastic mechanics, the strip travel trajectory of the bending roll straightening process is analyzed, and the numerical analytical calculation method of the continuous straightening process of the strip bending roll is established. The results are verified by establishing MARC finite element simulation and designing straightening experiment. The effects of yield strength, plastic rate and bending amount on residual stress after straightening were studied. In the straightening process, with the increase of the amount of bending roll, the residual strain converges to the region Γ, and with the increase of the yield strength, the region Γ decreases. With the increase of the yield strength, the amount of bending roll and the plastic rate, the wave height increases. The results of the calculation of residual stress, finite element simulation and experiment are close and the trend is consistent. The results show that the logic of the calculation method is reasonable, and the prediction error is within the scope of engineering application, which is helpful to the realization of process intelligence in the process of bending roller straightening.
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Affiliation(s)
- Xiaoyu Zhu
- Engineering Research Center Heavy Machinery Ministry of Education, Taiyuan University of Science and Technology, Taiyuan, 030024, Shanxi, China
| | - XiaoGang Wang
- Engineering Research Center Heavy Machinery Ministry of Education, Taiyuan University of Science and Technology, Taiyuan, 030024, Shanxi, China.
| | - Huihai Wu
- Engineering Research Center Heavy Machinery Ministry of Education, Taiyuan University of Science and Technology, Taiyuan, 030024, Shanxi, China
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Lohbauer U, Fabris DCN, Lubauer J, Abdelmaseh S, Cicconi MR, Hurle K, de Ligny D, Goetz-Neunhoeffer F, Belli R. Glass science behind lithium silicate glass-ceramics. Dent Mater 2024:S0109-5641(24)00066-6. [PMID: 38580561 DOI: 10.1016/j.dental.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/07/2024]
Abstract
OBJECTIVES Lithium silicate-based glass ceramics have evolved as a paramount restorative material in restorative and prosthetic dentistry, exhibiting outstanding esthetic and mechanical performance. Along with subtractive machining techniques, this material class has conquered the market and satisfied the patients' needs for a long-lasting, excellent, and metal-free alternative for single tooth replacements and even smaller bridgework. Despite the popularity, not much is known about the material chemistry, microstructure and terminal behaviour. METHODS This article combines a set of own experimental data with extensive review of data from literature and other resources. Starting at manufacturer claims on unique selling propositions, properties, and microstructural features, the aim is to validate those claims, based on glass science. Deep knowledge is mandatory for understanding the microstructure evolution during the glass ceramic process. RESULTS Fundamental glass characteristics have been addressed, leading to formation of time-temperature-transformation (TTT) diagrams, which are the basis for kinetic description of the glass ceramic process. Nucleation and crystallization kinetics are outlined in this contribution as well as analytical methods to describe the crystalline fraction and composition qualitatively and quantitatively. In relation to microstructure, the mechanical performance of lithium silicate-based glass ceramics has been investigated with focus on fracture strength versus fracture toughness as relevant clinical predictors. CONCLUSION Fracture toughness has been found to be a stronger link to initially outlined manufacturer claims, and to more precisely match ISO recommendations for clinical indications.
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Affiliation(s)
- Ulrich Lohbauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
| | - Débora Cristina Niero Fabris
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Julia Lubauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Samuel Abdelmaseh
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department Werkstoffwissenschaften, Institut für Glas und Keramik, Martensstrasse 5, 91058 Erlangen, Germany
| | - Maria-Rita Cicconi
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department Werkstoffwissenschaften, Institut für Glas und Keramik, Martensstrasse 5, 91058 Erlangen, Germany
| | - Katrin Hurle
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Mineralogy, Schlossgarten 5a, 91054 Erlangen, Germany
| | - Dominique de Ligny
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department Werkstoffwissenschaften, Institut für Glas und Keramik, Martensstrasse 5, 91058 Erlangen, Germany
| | - Friedlinde Goetz-Neunhoeffer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Mineralogy, Schlossgarten 5a, 91054 Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
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DeCarvalho S, Aljarrah O, Chen Z, Li J. Influence of build orientation and support structure on additive manufacturing of human knee replacements: a computational study. Med Biol Eng Comput 2024:10.1007/s11517-024-03038-7. [PMID: 38433178 DOI: 10.1007/s11517-024-03038-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 01/29/2024] [Indexed: 03/05/2024]
Abstract
Developing patient-specific implants has an increasing interest in the application of emerging additive manufacturing (AM) technologies. On the other hand, despite advances in total knee replacement (TKR), studies suggest that up to 20% of patients with elective TKR are dissatisfied with the outcome. By creating 3D objects from digital models, AM enables the production of patient-specific implants with complex geometries, such as those required for knee replacements. Previous studies have highlighted concerns regarding the risk of residual stresses and shape distortions in AM parts, which could lead to structural failure or other complications. This article presents a computational framework that uses CT images to create patient-specific finite element models for optimizing AM knee replacements. The workflow includes image processing in the open-source software 3DSlicer and MeshLab and AM process simulations in the commercial platform 3DEXPERIENCE. The approach is demonstrated on a distal femur replacement for a 50-year-old male patient from the open-access Natural Knee Data. The results show that build orientations have a significant impact on both shape distortions and residual stresses. Support structures have a marginal effect on residual stresses but strongly influence shape distortions, whereas conical support exhibits a maximum distortion of 18.5 mm. Future research can explore how these factors affect the functionality of AM knee replacements under in-service loading.
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Affiliation(s)
- Stephanie DeCarvalho
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, 285 Old Westport Road, Dartmouth, MA, 02747, USA
| | - Osama Aljarrah
- Department of Industrial and Manufacturing Engineering, Kettering University, 1700 University Ave, Flint, MI, 48504, USA
| | - Zi Chen
- Division of Thoracic Surgery, Brigham & Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA, 02115, USA
| | - Jun Li
- Department of Mechanical Engineering, University of Massachusetts Dartmouth, 285 Old Westport Road, Dartmouth, MA, 02747, USA.
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Burgmann S, Lid M, Johnsen H, Vedvik N, Haugen B, Provine J, van Helvoort A, Torgersen J. New avenues for residual stress analysis in ultrathin atomic layer deposited free-standing membranes through release of micro-cantilevers. Heliyon 2024; 10:e26420. [PMID: 38434070 PMCID: PMC10906182 DOI: 10.1016/j.heliyon.2024.e26420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 02/13/2024] [Indexed: 03/05/2024] Open
Abstract
The fabrication of thinnest, yet undeformed membrane structures with nanometer resolution is a prerequisite for a variety of Microelectromechanical systems (MEMS). However, functionally relevant thin films are susceptible to growth-generated stress. To tune the performance and reach large aspect ratios, knowledge of the intrinsic material properties is indispensable. Here, we present a new method for stress evaluation through releasing defined micro-cantilever segments by focused ion beam (FIB) milling from a predefined free-standing membrane structure. Thereby, the cantilever segment is allowed to equilibrate to a stress-released state through measurable strain in the form of a resulting radius of curvature. This radius can be back-calculated to the residual stress state. The method was tested on a 20 nm and 50 nm thick tunnel-like ALD Image 1 membrane structure, revealing a significant amount of residual stress with 866 MPa and 6104 MPa, respectively. Complementary finite element analysis to estimate the stress distribution in the structure showed a 97% and 90% agreement in out-of-plane deflection for the 20 nm and 50 nm membranes, respectively. This work reveals the possibilities of releasing entire membrane segments from thin film membranes with a significant amount of residual stress and to use the resulting bending behavior for evaluating stress and strain by measuring their deformation.
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Affiliation(s)
- S. Burgmann
- Department of Mechanical and Industrial Engineering, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | - M.J. Lid
- Department of Mechanical and Industrial Engineering, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | - H.J.D. Johnsen
- Department of Mechanical and Industrial Engineering, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | - N.P. Vedvik
- Department of Mechanical and Industrial Engineering, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | - B. Haugen
- Department of Mechanical and Industrial Engineering, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | | | - A.T.J. van Helvoort
- Department of Physics, NTNU, Trondheim, Norwegian University of Science and Technology, Norway
| | - J. Torgersen
- Chair of Materials Science, Department of Materials Engineering, TUM School of Engineering and Design, Technical University of Munich, Germany
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Lagos M, Retamal C, Valle R, Paredes R. Mathematical model for the plastic flow and ductile fracture of polycrystalline solids. Heliyon 2024; 10:e25348. [PMID: 38327426 PMCID: PMC10847659 DOI: 10.1016/j.heliyon.2024.e25348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 01/11/2024] [Accepted: 01/25/2024] [Indexed: 02/09/2024] Open
Abstract
It is mathematically shown that ductile fracture after finite plastic strain is a necessary consequence of the polycrystalline nature of the materials. A closed-form equation for the plastic strain to fracture of a fine-grained polycrystal with no voids is derived. The mathematical model for the plastic deformation is grounded on the physical hypothesis that adjacent grains slide with a relative velocity proportional to the local shear stress resolved in the plane of the shared grain boundary, when exceeds a finite threshold. Hence plastic flow is governed predominantly by the in-plane shear forces making grain boundaries to slide, and the induced local forces responsible for the continuous grain reshaping are much weaker. The process is shown to produce a monotonic hydrostatic pressure variation with strain that precludes a stationary flow. The hydrostatic pressure dependence on strain has two solutions. One of them leads to superplasticity, the other one is shown to diverge logarithmically at a finite fracture strain and then represents ductile behaviour. Emphasis is done in the mathematical aspects of the deformation of the polycrystal up to the initiation of fracture. Although theoretical predictions agree well with mechanical tests of commercial alloys, technical issues like the effects of the presence and evolution of porosity and other imperfections, or how fracture evolves after initiation are left for a more specific communication.
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Affiliation(s)
- Miguel Lagos
- Facultad de Ingeniería, Universidad de Talca, Campus Los Niches, Curicó, Chile
| | - César Retamal
- Facultad de Ingeniería, Universidad de Talca, Campus Los Niches, Curicó, Chile
| | - Rodrigo Valle
- Facultad de Ingeniería, Universidad de Talca, Campus Los Niches, Curicó, Chile
| | - Rodrigo Paredes
- Facultad de Ingeniería, Universidad Finis Terrae, Av. Pedro de Valdivia 1509, Providencia, Santiago, Chile
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Sanjuán M, Brizuela-Velasco A, Gil J, Cerrolaza M, Montalvillo E, Fernández-Hernández S, Robles D. Hybrid surface implants: Influence of residual stress on mechanical behavior, evaluated by finite element analysis and validation by fatigue tests. Dent Mater 2024; 40:9-18. [PMID: 37858421 DOI: 10.1016/j.dental.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023]
Abstract
OBJECTIVES To determine the influence of different surface roughness and residual stress of hybrid surface implants on their behavior and mechanical failure. METHODS Three types of implants with different surface roughness were used as specimens: smooth, rough, and hybrid. A diffractometer was used to determine the residual stress of the implants according to their different surface treatment. These results were used as an independent variable in a finite element analysis that compared the three specimens to determine the von Mises stress transferred to the implants and supporting bone and the resulting microdeformations. Flexural strength and fatigue behavior tests were performed to compare the results of the three types of implants. RESULTS Higher residual stress values were found for rough surfaces (p < 0.05, Student's t-test) compared to smooth surfaces, and both types of stress were different for the two types of hybrid implant surfaces. Finite element analysis found different von Mises stress and microdeformation results, both at the level of the implant and the bone, for the three types of implants under study. These results were correlated with the different flexural strength behaviors (lower resistance for hybrids and higher for rough surfaces, p < 0.05) and fatigue behavior (the rough implant had the longest fatigue life, while the hybrid implant exhibited the worst fatigue behavior). SIGNIFICANCE The results show a trend toward a less favorable mechanical behavior of the hybrid implants related to the retention of different residual stresses caused by the surface treatment.
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Affiliation(s)
- Marta Sanjuán
- Bioengineering Institute of Technology, International University of Catalonia, Barcelona, Spain
| | - Aritza Brizuela-Velasco
- DENS-ia Research Group, Faculty of Health Sciences, Miguel de Cervantes European University, Valladolid, Spain.
| | - Javier Gil
- Bioengineering Institute of Technology, International University of Catalonia, Barcelona, Spain
| | - Miguel Cerrolaza
- Bioengineering Institute of Technology, International University of Catalonia, Barcelona, Spain
| | - Enrique Montalvillo
- Bioengineering Institute of Technology, International University of Catalonia, Barcelona, Spain; DENS-ia Research Group, Faculty of Health Sciences, Miguel de Cervantes European University, Valladolid, Spain
| | - Saray Fernández-Hernández
- DENS-ia Research Group, Faculty of Health Sciences, Miguel de Cervantes European University, Valladolid, Spain
| | - Daniel Robles
- DENS-ia Research Group, Faculty of Health Sciences, Miguel de Cervantes European University, Valladolid, Spain
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Liu C, Eser A, Heintze S, Rothbrust F, Broeckmann C. Computation of the fracture probability and lifetime of all ceramic anterior crowns under cyclic loading - An FEA study. Dent Mater 2023; 39:965-976. [PMID: 37690952 DOI: 10.1016/j.dental.2023.08.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023]
Abstract
OBJECTIVES To predict the lifetime and fracture probability of anterior crowns made of a lithium disilicate glass-ceramic (IPS e.max CAD, LD, Ivoclar Vivadent, Liechtenstein) and a zirconia-containing lithium silicate glass-ceramic (Celtra Duo, ZLS, Dentsply Sirona, USA) under cycling loading. METHODS Three-point bending tests were conducted to measure the viscoelastic parameters. These parameters are used to compute the residual stresses of the anterior crown after crystallization. In the next analysis, the cyclic loading on the anterior crown was calculated. Based on this combined stress state (residual stress and stress state due to external cyclic loading), the life cycle and fracture probability of the anterior crown was calculated using the CARES/Life software. Finally, fatigue experiments were carried out to compare and validate the results of the computations. RESULTS Although a sound qualitative comparison of the lifetime of both materials can be done using this methodology, the calculated fracture probability of the anterior crown for both materials was very low in comparison with the fatigue test results using the fatigue parameters determined from the experiments. In order to achieve good correspondence with the experimental results, the SCG exponent n for both materials should be modified by a correlation factor of 0.38. SIGNIFICANCE Using this modified computational strategy, the results of the time-consuming fatigue tests for dental glass-ceramics can be closely predicted. This methodology can be integrated into the development process of new glass-ceramic materials in order to save time and costs.
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Affiliation(s)
- Chao Liu
- IWM, RWTH-Aachen, Augustinerbach 4, D-52062 Aachen, Germany
| | - Atilim Eser
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein.
| | - Siegward Heintze
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | - Frank Rothbrust
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
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Ghadie NM, Labrosse MR, St-Pierre JP. Glycosaminoglycans modulate compressive stiffness and circumferential residual stress in the porcine thoracic aorta. Acta Biomater 2023; 170:556-566. [PMID: 37683966 DOI: 10.1016/j.actbio.2023.08.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/26/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023]
Abstract
The mechanical properties of the aorta are influenced by the extracellular matrix, a network mainly comprised of fibers and glycosaminoglycans (GAG). In this work, we demonstrate that GAG contribute to the opening angle (a marker of circumferential residual stresses) in intact and glycated aortic tissue. Enzymatic GAG depletion was associated with a decrease in the opening angle, by approximately 25% (p = 0.009) in the ascending (AS) region, 32% (p = 0.003) in the aortic arch (AR), and 42% (p = 0.001) in the lower descending thoracic (LDT) region. A similar effect of GAG depletion on aortic ring opening angle was also observed in previously glycated tissues. Using indentation testing, we found that the radial compressive stiffness significantly increased in the AS region following GAG depletion, compared to fresh (p = 0.006) and control samples (p = 0.021), and that the compressive properties are heterogeneous along the aortic tree. A small loss of water content was also detected after GAG depletion, which was most prominent under hypotonic conditions. Finally, the AS region was also associated with a significant loss of compressive deformation (circumferential stretch that is < 1) in the inner layer of the aorta following GAG depletion, suggesting that GAG interact with ECM fibers in their effect on aortic mechanics. The importance of this work lies in its identification of the role of GAG in modulating the mechanical properties of the aorta, namely the circumferential residual stresses and the radial compressive stiffness, as well as contributing to the swelling state and the level of circumferential prestretch in the tissue. STATEMENT OF SIGNIFICANCE: The mechanical properties of the aorta are influenced by the composition and organization of its extracellular matrix (ECM) and are highly relevant to medical conditions affecting the structural integrity of the aorta. The extent of contribution of glycosaminoglycans (GAG), a relatively minor ECM component, to the mechanical properties of the aorta, remains poorly characterized. This works shows that GAG contribute on average 30% to the opening angle (an indicator of circumferential residual stresses) of porcine aortas, and that GAG-depletion is associated with an increased radial compressive stiffness of the aorta. GAG-depletion was also associated with a loss of water content and compressive deformation in the inner layers of the aortic wall providing insight into potential mechanisms for their biomechanical role.
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Affiliation(s)
- Noor M Ghadie
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada
| | - Michel R Labrosse
- Department of Mechanical Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada; Department of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON K1Y4W7, Canada
| | - Jean-Philippe St-Pierre
- Department of Chemical and Biological Engineering, University of Ottawa, Ottawa, ON K1N6N5, Canada.
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Shishido S, Inagaki R, Kanno T, Svanborg P, Barkarmo S, Örtengren U, Nakamura K. Residual stress associated with crystalline phase transformation of 3-6 mol% yttria-stabilized zirconia ceramics induced by mechanical surface treatments. J Mech Behav Biomed Mater 2023; 146:106067. [PMID: 37567065 DOI: 10.1016/j.jmbbm.2023.106067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023]
Abstract
Monolithic dental prostheses made of 3-6 mol% yttria-stabilized zirconia (3-6YSZ) have gained popularity owing to their improved material properties and semi-automated fabrication processes. In this study, we aimed to evaluate the influence of mechanical surface treatments, such as polishing, grinding, and sandblasting, on the residual stress of 3-6YSZ used for monolithic prostheses in association with crystalline phase transformation. Plate specimens were prepared from five dental zirconia blocks: Aadva Zirconia ST (3YSZ), Aadva Zirconia NT (6YSZ), Katana HT (4YSZ), Katana STML (5YSZ), and Katana UTML (6YSZ). The specimens were either polished using 1, 3, or 9 μm diamond suspensions, ground using 15, 35, or 55 μm diamond discs, or sandblasted at 0.2, 0.3, or 0.4 MPa. The residual stress, crystalline phase, and hardness were analyzed using the cosα method, X-ray diffraction (XRD), and Vickers hardness test, respectively. Additionally, we analyzed the residual stress on the surfaces of monolithic zirconia crowns (MZCs) made of 4YSZ, 5YSZ, and 6YSZ, which were processed using clinically relevant procedures, including manual grinding, followed by polishing using a dental electric motor on the external surface, and sandblasting on the internal surface. Residual stress analysis demonstrated that grinding and sandblasting, particularly the latter, resulted in the generation of compressive residual stress on the surfaces of the plate specimens. XRD revealed that the ground and sandblasted specimens contained a larger amount of the rhombohedral phase than that of the polished specimens, which may be a cause of the residual stress. Sandblasting significantly increased the Vickers hardness compared to polishing, which may possibly be due to the generation of compressive residual stress. In the case of MZCs, compressive residual stress was detected not only on the sandblasted surface, but also on the polished surface. The difference in the residual stress between the plate and crown specimens may be related to the force applied during the automated and manual grinding and polishing procedures. Further studies are required to elucidate the effects of the compressive residual stress on the clinical performance of MZCs.
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Affiliation(s)
- Shunichi Shishido
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980 8575, Japan.
| | - Ryoichi Inagaki
- Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980 8575, Japan
| | - Taro Kanno
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980 8575, Japan
| | - Per Svanborg
- Department of Prosthetic Dentistry / Dental Materials Science, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Sargon Barkarmo
- Department of Prosthetic Dentistry / Dental Materials Science, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Ulf Örtengren
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Keisuke Nakamura
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980 8575, Japan
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Hadjigeorgiou AG, Stylianopoulos T. Evaluation of growth-induced, mechanical stress in solid tumors and spatial association with extracellular matrix content. Biomech Model Mechanobiol 2023; 22:1625-1643. [PMID: 37129689 DOI: 10.1007/s10237-023-01716-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/27/2023] [Indexed: 05/03/2023]
Abstract
Mechanical stresses in solid tumors play an important role in tumor progression and treatment efficacy but their quantification is under-investigated. Here, we developed an experimental and computational approach to calculate growth-induced, residual stresses and applied it to the breast (4T1), pancreatic (PAN02), and fibrosarcoma (MCA205) tumor models. Following resection, tumors are embedded in agarose gels and cuts are made in two perpendicular directions to release residual stress. With the use of image processing, the detailed bulging displacement profile is measured and finite elements models of the bulging geometry are developed for the quantification of the stress levels. The mechanical properties of the tumors are measured in vivo prior to resection with shear wave elastography. We find that the average magnitude of residual stresses ranges from 3.31 to 10.88 kPa, and they are non-uniformly distributed within the tissue due to the heterogeneity of the tumor microenvironment. Interestingly, we demonstrate that a second cut can still release a significant amount of stresses. We further find a strong association of spatial hyaluronan and collagen content with the spatial profile of stress for the MCA205 and PAN02 tumors and a partial association for the 4T1. Interestingly the colocalization of hyaluronan and collagen content had a stronger association with the spatial profile of stress for MCA205, PAN02, and 4T1. Finally, measurements of the elastic modulus with shear wave elastography show a nonlinear correlation with tumor volume for the more fibrotic MCA205 and 4T1 tumors. Overall, our results provide insights for a better understanding of the mechanical behavior of tumors.
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Affiliation(s)
- Andreas G Hadjigeorgiou
- Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus
| | - Triantafyllos Stylianopoulos
- Cancer Biophysics Laboratory, Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, Cyprus.
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12
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Borhani MR, Rajabi M, Shoja Razavi R, Jamaati R. Investigating the relationship between mechanical properties and residual stress in the laser cladding process of Inconel 625 superalloy. Heliyon 2023; 9:e19791. [PMID: 37809515 PMCID: PMC10559123 DOI: 10.1016/j.heliyon.2023.e19791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 10/10/2023] Open
Abstract
In the present study, the tensile strength, fracture surface, hardness, and amount of residual stress in Inconel 625 super alloy cladded with direct metal deposition (DLD) process in the states before and after stress relief was studied. Residual stresses on the cladding layer surface were determined via XRD method. According to results, the yield strength of Am sample increased by 10% compared to thecast sample (reference sample). Although the yield strength experiebced an increase, the ductility followed an opposite trend falling from 42.5% to 26%. According to residual stress test outcomes, tensile residual stress of 361 MPa in the additive-manufactured sample. After stress relaxation heat treatment and almost complete removal of residual stress, the ductility reached 52.5%, the ultimate strength was also improved by 17% from cast sample. Also, after stress relaxation, the hardness of the sample and its fluctuations are reduced.
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Affiliation(s)
- Mohammad Reza Borhani
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
| | - Mohammad Rajabi
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
| | - Reza Shoja Razavi
- Faculty of Materials & Manufacturing Technologies, Malek Ashtar University of Technology, Iran
| | - Roohollah Jamaati
- Department of Materials Engineering, Babol Noshirvani University of Technology, Babol, 47148-71167, Iran
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13
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Klockars KW, Greca LG, Majoinen J, Mihhels K, Rojas OJ, Tardy BL. Drying stresses in cellulose nanocrystal coatings: Impact of molecular and macromolecular additives. Carbohydr Polym 2023; 303:120465. [PMID: 36657848 DOI: 10.1016/j.carbpol.2022.120465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 12/07/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022]
Abstract
The industrial implementation of cellulose nanocrystals (CNCs) in films and coatings requires thorough evaluation of the internal stresses post-consolidation, as they cause fracturing and peeling. Characterizing the impact of plasticizing additives on stress is therefore critical. Herein, we use the deflection of thin glass substrates to measure drying stresses in consolidating CNC films, and benchmark the impact of five additives (glucose, glycerol, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA) and bovine serum albumin). Glycerol and PEG reduced drying stresses effectively, while PEG of increased molecular weight (from 0.2 to 10 kDa), PVA, and BSA were less effective. We analyzed the temporal aspects of the process, where stress relaxation of up to 30 % was observed 2 years after coating formation. Finally, we provide a framework to evaluate the impact of CNC morphology on residual stresses. The introduced approach is expected to fast-track the optimization and implementation of coatings based on biocolloids.
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Affiliation(s)
- Konrad W Klockars
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Luiz G Greca
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Johanna Majoinen
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Karl Mihhels
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Orlando J Rojas
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland; Bioproducts Institute, Department of Chemical and Biological Engineering, Department of Chemistry and Department of Wood Science, University of British Columbia, 2360 East Mall, Vancouver, BC V6T 1Z4, Canada.
| | - Blaise L Tardy
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland; Department of Chemical Engineering, Khalifa University, Abu Dhabi, United Arab Emirates.
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14
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Monu MCC, Afkham Y, Chekotu JC, Ekoi EJ, Gu H, Teng C, Ginn J, Gaughran J, Brabazon D. Bi-directional Scan Pattern Effects on Residual Stresses and Distortion in As-built Nitinol Parts: A Trend Analysis Simulation Study. Integr Mater Manuf Innov 2023; 12:52-69. [PMID: 36873293 PMCID: PMC9974685 DOI: 10.1007/s40192-023-00292-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
In this paper, a part-scale simulation study on the effects of bi-directional scanning patterns (BDSP) on residual stress and distortion formation in additively manufactured Nitinol (NiTi) parts is presented. The additive manufacturing technique of focus is powder bed fusion using a laser beam (PBF-LB), and simulation was performed using Ansys Additive Print software. The numerical approach adopted in the simulation was based on the isotropic inherent strain model, due to prohibitive material property requirements and computational limitations of full-fledged part-scale 3D thermomechanical finite element approaches. In this work, reconstructed 2D and 3D thermograms (heat maps) from in situ melt pool thermal radiation data, the predicted residual stresses, and distortions from the simulation study were correlated for PBF-LB processed NiTi samples using selected BDSPs. The distortion and residual stress distribution were found to vary greatly between BDSPs with no laser scan vector rotations per new layer, whereas negligible variations were observed for BDSPs with laser scan vector rotations per new layer. The striking similarities between the reconstructed thermograms of the first few layers and the simulated stress contours of the first lumped layer provide a practical understanding of the temperature gradient mechanism of residual stress formation in PBF-LB processed NiTi. This study provides a qualitative, yet practical insight towards understanding the trends of formation and evolution of residual stress and distortion, due to scanning patterns.
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Affiliation(s)
- Medad C. C. Monu
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
- School of Physics, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland
| | - Yalda Afkham
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
- School of Physics, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland
| | - Josiah C. Chekotu
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
- School of Physics, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland
| | - Emmanuel J. Ekoi
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
| | - Hengfeng Gu
- Ansys, Inc., 1441 West Ute Blvd, Suite #335, Park City, UT 84098 USA
| | - Chong Teng
- Ansys, Inc., 1441 West Ute Blvd, Suite #335, Park City, UT 84098 USA
| | - Jon Ginn
- Ansys, Inc., 1441 West Ute Blvd, Suite #335, Park City, UT 84098 USA
| | - Jennifer Gaughran
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
- School of Physics, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland
| | - Dermot Brabazon
- I-Form Advanced Manufacturing Research Center, Advanced Processing Technology Research Center, Dublin City University, Dublin, Ireland
- School of Physics, School of Mechanical and Manufacturing Engineering, Dublin City University, Dublin, Ireland
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15
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Praniewicz M, Fox JC, Tarr J. Part Deflection Measurements of AM-Bench IN718 3D Build Artifacts. Integr Mater Manuf Innov 2023; 12:386-396. [PMID: 38410829 PMCID: PMC10895932 DOI: 10.1007/s40192-023-00310-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/07/2023] [Indexed: 02/28/2024]
Abstract
One of the primary barriers for adoption of additive manufacturing (AM) had been the uncertainty in the performance of AM parts due to residual stresses/strains. The rapid melting and solidification which occurs during AM processes result in high residual stresses/strains that produce significant part distortion. While efforts to mitigate residual stresses, such as post-process heat treatment, can reduce these effects, they nullify the benefits of the as-built component microstructure. Therefore, the ability to predict as-built component residual stresses and component deflection is crucial. AM-Bench seeks to provide modelers with high-fidelity data in well-characterized AM components to aid in model development and calibration. The measurements reported here are part of the 3D builds of nickel-based superalloy IN718 test objects for the CHAL-AMB2022-01-PD modeling challenges. The part deflection measurements were performed using a coordinate measurement machine after the part was partially separated from the build plate.
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Affiliation(s)
- Maxwell Praniewicz
- Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jason C Fox
- Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Jared Tarr
- Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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16
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Zhao Y, Liu C, Zhao Z, Tang K, He D. Reinforcement learning method for machining deformation control based on meta-invariant feature space. Vis Comput Ind Biomed Art 2022; 5:27. [PMID: 36418749 PMCID: PMC9684396 DOI: 10.1186/s42492-022-00123-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/16/2022] [Indexed: 11/25/2022] Open
Abstract
Precise control of machining deformation is crucial for improving the manufacturing quality of structural aerospace components. In the machining process, different batches of blanks have different residual stress distributions, which pose a significant challenge to machining deformation control. In this study, a reinforcement learning method for machining deformation control based on a meta-invariant feature space was developed. The proposed method uses a reinforcement-learning model to dynamically control the machining process by monitoring the deformation force. Moreover, combined with a meta-invariant feature space, the proposed method learns the internal relationship of the deformation control approaches under different stress distributions to achieve the machining deformation control of different batches of blanks. Finally, the experimental results show that the proposed method achieves better deformation control than the two existing benchmarking methods.
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Affiliation(s)
- Yujie Zhao
- grid.64938.300000 0000 9558 9911College of Mechanical and Electrical Engineering/National Key Laboratory of Science and Technology on Helicopter Transmission, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 China
| | - Changqing Liu
- grid.64938.300000 0000 9558 9911College of Mechanical and Electrical Engineering/National Key Laboratory of Science and Technology on Helicopter Transmission, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 China
| | - Zhiwei Zhao
- grid.64938.300000 0000 9558 9911College of Mechanical and Electrical Engineering/National Key Laboratory of Science and Technology on Helicopter Transmission, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 China
| | - Kai Tang
- grid.24515.370000 0004 1937 1450The Smart Manufacturing Thrust, Hong Kong University of Science and Technology (GZ), Guangzhou, 511458 China
| | - Dong He
- grid.24515.370000 0004 1937 1450The Smart Manufacturing Thrust, Hong Kong University of Science and Technology (GZ), Guangzhou, 511458 China
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17
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Pei N, Zhao B, Bond LJ, Xu C. Analysis of the directivity of longitudinal waves based on double-fold coil phased EMAT. Ultrasonics 2022; 125:106788. [PMID: 35709573 DOI: 10.1016/j.ultras.2022.106788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 06/03/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
Longitudinal critically refracted (LCR) waves have already been widely applied for residual stress characterization. Such waves are usually generated using mode-conversion at the first critical angle of the incident longitudinal wave, which gives waves that then propagate at a dip-angle, and this places energy close to the surface of the specimen. The dip-angle needs to be minimized to improve both velocity measurement and residual stress characterization sensitivity. This paper reports a novel double-fold coil phased EMAT that can decrease the dip-angle. The performance of this new EMAT was investigated using both a COMSOL model and experiments. Initial model validation was provided through a comparison with experimental data. The EMAT design also enables scanning of samples, and operation in harsh environments where use of a PZT based transducer and couplants can complicate and limit inspection. The use of the EMAT has the potential to give more accurate time of flight (TOF) data and enhances the reliability and accuracy for residual stress measurement.
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Affiliation(s)
- Ning Pei
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081, China
| | - Bin Zhao
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China
| | - Leonard J Bond
- Department of Aerospace Engineering & Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50010, USA.
| | - Chunguang Xu
- School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China; Key Laboratory of Fundamental Science for Advanced Machining, Beijing Institute of Technology, Beijing 100081, China
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18
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Li Y, Zhang D, Wang H, Ye G, He R, Cong W. Theoretical and experimental investigations on rotary ultrasonic surface micro-machining of brittle materials. Ultrason Sonochem 2022; 89:106162. [PMID: 36113208 PMCID: PMC9482144 DOI: 10.1016/j.ultsonch.2022.106162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/22/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
Many brittle materials, such as single-crystal materials, amorphous materials, and ceramics, are widely used in many industries such as the energy industry, aerospace industry, and biomedical industry. In recent years, there is an increasing demand for high-precision micro-machining of these brittle materials to produce precision functional parts. Traditional ultra-precision micro-machining can lead to workpiece cracking, low machined surface quality, and reduced tool life. To reduce and further solve these problems, a new micro-machining process is needed. As one of the nontraditional machining processes, rotary ultrasonic machining is an effective method to reduce the issues generated by traditional machining processes of brittle materials. Therefore, rotary ultrasonic micro-machining (RUμM) is investigated to conduct the surface micro-machining of brittle materials. Due to the small diameter cutting tool (<500 μm) and high accuracy requirements, the impact of input parameters in the rotary ultrasonic surface micro-machining (RUSμM) process on tool deformation and cutting quality is extremely different from that in rotary ultrasonic surface machining (RUSM) with relatively large diameter cutting tool (∼10 mm). Up till now, there is still no investigation on the effects of ultrasonic vibration (UV) and input variables (such as tool rotation speed and depth of cut) on cutting force and machined surface quality in RUSμM of brittle materials. To fill this knowledge gap, rotary ultrasonic surface micro-machining of the silicon wafer (one of the most versatile brittle materials) was conducted in this study. The effects of ultrasonic vibration, tool rotation speed, and depth of cut on tool trajectory, material removal rate (MRR), cutting force, cutting surface quality, and residual stress were investigated. Results show that the ultrasonic vibration could reduce the cutting force, improve the cutting surface quality, and suppress the residual compressive stress, especially under conditions with high tool rotation speed.
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Affiliation(s)
- Yunze Li
- Department of Industrial, Manufacturing, and Systems Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Dongzhe Zhang
- Department of Industrial, Manufacturing, and Systems Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Hui Wang
- Department of Industrial & Systems Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Gaihua Ye
- Department of Electrical & Computer Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Rui He
- Department of Electrical & Computer Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Weilong Cong
- Department of Industrial, Manufacturing, and Systems Engineering, Texas Tech University, Lubbock, TX 79409, USA.
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19
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Zhang W, Sommer G, Niestrawska JA, Holzapfel GA, Nordsletten D. The effects of viscoelasticity on residual strain in aortic soft tissues. Acta Biomater 2022; 140:398-411. [PMID: 34823042 DOI: 10.1016/j.actbio.2021.11.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/14/2021] [Accepted: 11/15/2021] [Indexed: 11/15/2022]
Abstract
Residual stress is thought to play a critical role in modulating stress distributions in soft biological tissues and in maintaining the mechanobiological stress environment of cells. Residual stresses in arteries and other tissues are classically assessed through opening angle experiments, which demonstrate the continuous release of residual stresses over hours. These results are then assessed through nonlinear biomechanical models to provide estimates of the residual stresses in the intact state. Although well studied, these analyses typically focus on hyperelastic material models despite significant evidence of viscoelastic phenomena over both short and long timescales. In this work, we extended the state-of-the-art structural tensor model for arterial tissues from Holzapfel and Ogden for fractional viscoelasticity. Models were tuned to capture consistent levels of hysteresis observed in biaxial experiments, while also minimizing the fractional viscoelastic weighting and opening angles to correctly capture opening angle dynamics. Results suggest that a substantial portion of the human abdominal aorta is viscoelastic, but exhibits a low fractional order (i.e. more elastically). Additionally, a significantly larger opening angle in the fully unloaded state is necessary to produce comparable hysteresis in biaxial testing. As a consequence, conventional estimates of residual stress using hyperelastic approaches over-estimate their viscoelastic counterparts by a factor of 2. Thus, a viscoelastic approach, such as the one illustrated in this study, in combination with an additional source of rate-controlled viscoelastic data is necessary to accurately analyze the residual stress distribution in soft biological tissues. STATEMENT OF SIGNIFICANCE: Residual stress plays a crucial role in achieving a homeostatic stress environment in soft biological tissues. However, the analysis of residual stress typically focuses on hyperelastic material models despite evidence of viscoelastic behavior. This work is the first attempt at analyzing the effects of viscoelasticity on residual stress. The application of viscoelasticity was crucial for producing realistic opening dynamics in arteries. The overall residual stresses were estimated to be 50% less than those from using hyperelastic material models, while the opening angles were projected to be 25% more than those measured after 16 hours, suggesting underestimated residual strain. This study highlights the importance viscoelasticity in the analysis of residual stress even in weakly dissipative materials like the human aorta.
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Affiliation(s)
- Will Zhang
- Department of Biomedical Engineering, University of Michigan, North Campus Research Center, Building 20, 2800 Plymouth Rd, Ann Arbor 48109, USA.
| | - Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, AT, Austria
| | - Justyna A Niestrawska
- Gottfried Schatz Research Center, Division of Macroscopic and Clinical Anatomy, Medical University of Graz, Harrachgasse 21, 8010 Graz, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, AT, Austria; Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim, NO, Norway
| | - David Nordsletten
- Division of Biomedical Engineering and Imaging Sciences, Department of Biomedical Engineering, King's College London, UK; Departments of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, USA
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20
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Zhang Q, Zhao S, Ul Hassan Mohsan A, Yu L, Zhai M, Qi X. Numerical and experimental studies on needle impact characteristics in ultrasonic shot peening. Ultrasonics 2022; 119:106634. [PMID: 34781117 DOI: 10.1016/j.ultras.2021.106634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 06/13/2023]
Abstract
Ultrasonic shot peening(USP) is an advanced surface treatment technology for obtaining excellent surface properties or manufacturing a three-dimensional curved surface of the metal sheets. The impact of the medium driven by ultrasonic vibration is significant to parameter optimization and excellent performance of the USP technology. However, the impact characteristics of the medium lack careful study, which is a complex dynamic analysis involving many factors, such as collision, plastic deformation, air pressure, etc. In this paper, a detection system is successfully developed to investigate the needle impact force and frequency against the material surface, consisting of a piezoelectric load sensor, oscilloscope, and a single needle USP device. Moreover, the FE model of the needle impact is developed simultaneously to study the characteristics of residual stress implantation induced by needle impact. Based on the experiment and FE simulation results, it is discovered that the impacts with high speed primarily determine the thickness of the modified layer implanted with residual stress during multiple impacts at different rates. According to residual stress implantation characteristics, the low-speed impact whose speed does not reach 50% of the maximum impact speed was defined as the ineffective impact. Besides, increasing the amplitude of ultrasonic vibration results in a significant increase in the maximum impact force and the effective impact frequency. The travel distance of needle impact has a considerable effect on the effective impact frequency, but it has little effect on the maximum impact force. Finally, it was concluded that the low air pressure plays a positive role in the needle impact. Furthermore, excessive air pressure hinders the needle impact and results in a decline in the effective impact frequency and the maximum impact force.
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Affiliation(s)
- Qinglong Zhang
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China; Zhejiang Key Laboratory of Aero Engine Extreme Manufacturing Technology, Ningbo 315201, China.
| | - Su Zhao
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China; Zhejiang Key Laboratory of Aero Engine Extreme Manufacturing Technology, Ningbo 315201, China.
| | - Aziz Ul Hassan Mohsan
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China; Zhejiang Key Laboratory of Aero Engine Extreme Manufacturing Technology, Ningbo 315201, China
| | - Lei Yu
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China; Zhejiang Key Laboratory of Aero Engine Extreme Manufacturing Technology, Ningbo 315201, China
| | - Menggang Zhai
- Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, China; Zhejiang Key Laboratory of Aero Engine Extreme Manufacturing Technology, Ningbo 315201, China
| | - Xiaowen Qi
- School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China
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21
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Ghadie NM, St-Pierre JP, Labrosse MR. Intramural Distributions of GAGs and Collagen vs. Opening Angle of the Intact Porcine Aortic Wall. Ann Biomed Eng 2022; 50:157-168. [PMID: 35028784 DOI: 10.1007/s10439-022-02901-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 01/01/2022] [Indexed: 11/28/2022]
Abstract
The heterogeneity and contribution of collagen and elastin to residual stresses have been thoroughly studied, but more recently, glycosaminoglycans (GAGs) also emerged as potential regulators. In this study, the opening angle of aortic rings (an indicator of circumferential residual stresses) and the mural distributions of sulfated GAGs (sGAG), collagen, and elastin were quantified in the ascending, aortic arch and descending thoracic regions of 5- to 6-month-old pigs. The opening angle correlated positively with the aortic ring's mean radius and thickness, with good and moderate correlations respectively. The correlations between the sGAG, collagen, elastin, and collagen:sGAG ratio and the opening angle were evaluated to identify aortic compositional factors that could play roles in regulating circumferential residual stresses. The total collagen:sGAG ratio displayed the strongest correlation with the opening angle (r = - 0.715, p < 0.001), followed by the total sGAG content which demonstrated a good correlation (r = 0.623, p < 0.001). Additionally, the intramural gradients of collagen, sGAG and collagen:sGAG correlated moderately with the opening angle. We propose that, in addition to the individual role sGAG play through their content and intramural gradient, the interaction between collagen and sGAG should be considered when evaluating circumferential residual stresses in the aorta.
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Affiliation(s)
- Noor M Ghadie
- Mechanical Engineering Department, University of Ottawa, Ottawa, ON, K1N6N5, Canada
| | - Jean-Philippe St-Pierre
- Chemical and Biological Engineering Department, University of Ottawa, Ottawa, ON, K1N6N5, Canada
| | - Michel R Labrosse
- Mechanical Engineering Department, University of Ottawa, Ottawa, ON, K1N6N5, Canada. .,Department of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON, K1Y4W7, Canada.
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22
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Ko KH, Kang HG, Huh YH, Park CJ, Cho LR. Effects of heat treatment on the microstructure, residual stress, and mechanical properties of Co-Cr alloy fabricated by selective laser melting. J Mech Behav Biomed Mater 2021; 126:105051. [PMID: 34959095 DOI: 10.1016/j.jmbbm.2021.105051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 11/24/2022]
Abstract
The mechanical properties and residual stress of dental Co-Cr-Mo (CCM) alloy depend on the manufacturing and post-processing methods, which affect the prognosis of dental prostheses. Two CCM alloys manufactured by casting and selective laser melting (SLM) were compared, and the effect of heat treatment temperature for CCM alloys manufactured by SLM method was evaluated. Specimens were fabricated by casting (Cast Co-Cr) and SLM (SLM Co-Cr). SLM Co-Cr specimens were heat treated at 750, 950, and 1150 °C to compare their properties. Microstructures were analyzed via scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction (EBSD), and the residual stress was measured via x-ray diffraction (XRD). Mechanical properties were evaluated by a Vickers hardness test and a tensile test; fractography was performed after this. The SLM Co-Cr group exhibited a decrease in porosity, grain size, increase in solid solution limit, and high residual stress compared to Cast Co-Cr; the ultimate tensile strength, yield strength, and hardness were also higher. The microstructures, residual stresses, and mechanical properties differed significantly depending on the heat treatment, and the strength and hardness showed a tendency inverse to that of the elongation. Type I residual stresses mostly decreased after 750 °C heat treatment, however type II and III residual stresses remained even after 1150 °C heat treatment. SLM presented superior mechanical properties to casting. Considering the reduction of tensile residual stress and increased ductility, CCM alloys should be heat treated at a temperature of 950 °C or higher.
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Li XC, Li D, Zhang SF, Jing L, Zhou WH, He L, Yu S, Meng M. Effect of Li +/Na + exchange on mechanical behavior and biological activity of lithium disilicate glass-ceramic. J Mech Behav Biomed Mater 2021; 126:105036. [PMID: 34902754 DOI: 10.1016/j.jmbbm.2021.105036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/26/2022]
Abstract
Lithium disilicate (LD) glass-ceramics with a stoichiometric composition were ion-exchanged in pure NaNO3 or mixed NaNO3 + KNO3 molten salt baths below the glass transition temperature (Tg). The microstructures, surface morphologies, mechanical properties and bioactivities of the ion-exchanged glass-ceramics were studied in detail. It was found that the strength and toughness of LD glass-ceramic could be enhanced from 175 MPa to 0.96 MPa m1/2 before ion-exchange to 546 MPa and 4.31 MPa m1/2 respectively under a lowered ion-exchange temperature because the less stress relaxation. In addition, a gradient of Na+ rich layer in the surface of glass-ceramic was induced by Li+/Na+ exchange, which could be beneficial to the formation of HA (Hydroxyapatite) with nano-size porous after soaking in SBF (Simulated Body Fluid) solution and exhibited better bioactivity compared with the original LD glass-ceramic. The results might provide a reference for the strengthening and biological activation of LD glass-ceramics in bone restoration applications.
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Affiliation(s)
- X C Li
- Shaanxi Key Laboratory of Biomedical Metallic Materials, Northwest Institute for Non-ferrous Metal Research, Xi'an, 710016, China.
| | - D Li
- School of Science, Xi'an University of Posts and Telecommunications, Xi'an, 710121, China
| | - S F Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China
| | - L Jing
- Shaanxi Key Laboratory of Biomedical Metallic Materials, Northwest Institute for Non-ferrous Metal Research, Xi'an, 710016, China
| | - W H Zhou
- Shaanxi Key Laboratory of Biomedical Metallic Materials, Northwest Institute for Non-ferrous Metal Research, Xi'an, 710016, China
| | - L He
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - S Yu
- Shaanxi Key Laboratory of Biomedical Metallic Materials, Northwest Institute for Non-ferrous Metal Research, Xi'an, 710016, China.
| | - M Meng
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Prosthodontics, School of Stomatology, Fourth Military Medical University, Xi'an, 710032, China.
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Patel M, Savvopoulos F, Berggren CC, Aslanidou L, Timmins LH, de Silva R, Pedrigi RM, Krams R. Considerations for analysis of endothelial shear stress and strain in FSI models of atherosclerosis. J Biomech 2021; 128:110720. [PMID: 34482227 DOI: 10.1016/j.jbiomech.2021.110720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 07/15/2021] [Accepted: 08/23/2021] [Indexed: 11/23/2022]
Abstract
Atherosclerosis is a lipid driven chronic inflammatory disease that is characterized by the formation of plaques at predilection sites. These predilection sites (side branches, curved segments, and bifurcations) have often been associated with disturbed shear stress profiles. However, in addition to shear stress, endothelial cells also experience artery wall strain that could contribute to atherosclerosis progression. Herein, we describe a method to accurately obtain these shear stress and strain profiles. We developed a fluid-structure interaction (FSI) framework for modelling arteries within a commercially available package (Abaqus, version 6.14) that included known prestresses (circumferential, axial and pressure associated). In addition, we co-registered 3D histology to a micro-CT-derived 3D reconstruction of an atherosclerotic carotid artery from a cholesterol-fed ApoE-/- mouse to include the spatial distribution of lipids within a subject-specific model. The FSI model also incorporated a nonlinear hyperelastic material model with regionally-varying properties that distinguished between healthy vessel wall and plaque. FSI predicted a lower shear stress than CFD (~-12%), but further decreases in plaque regions with softer properties (~-24%) were dependent on the approach used to implement the prestresses in the artery wall. When implemented with our new hybrid approach (zero prestresses in regions of lipid deposition), there was significant heterogeneity in endothelial shear stress in the atherosclerotic artery due to variations in stiffness and, in turn, wall strain. In conclusion, when obtaining endothelial shear stress and strain in diseased arteries, a careful consideration of prestresses is necessary. This paper offers a way to implement them.
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Takamizawa K. Stretch and stress distributions in the human artery based on two-layer model considering residual stresses. Biomech Model Mechanobiol 2021. [PMID: 34622379 DOI: 10.1007/s10237-021-01523-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 09/23/2021] [Indexed: 10/20/2022]
Abstract
The objective is to know the stress distributions in the arterial walls under residual stresses based on two-layer model. Human common carotid arteries were analysed to show stress distributions at physiological and supraphysiological intraluminal pressures. The analyses for the loaded states were performed with stretch ratios with reference to a Riemannian stress-free configuration which is a 3D non-Euclidean manifold due to the nonzero Riemann curvature tensor. The experimental data obtained by other literature were used for the common carotid arteries to analyse the stretch and stress distributions in the arterial wall although kinematics is different from the literature. The stretches and stresses were calculated for the unloaded state, i.e. the residual stretches and stresses. And those at the axial stretch ratio 1.1 with reference to the unloaded state were calculated at the intraluminal pressures 16, 50, and 100 kPa. The stresses increased from the inner surface to the outer surface at all pressures analysed. These results suggest that in the human arteries the mechanical loads are mainly supported with the adventitia even though the media and intima play an important role to control of physiological functions.
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Sisodia RP, Gáspár M, Sepsi M, Mertinger V. Dataset on full width at half maximum of residual stress measurement of electron beam welded high strength structural steels (S960QL and S960M) by X-ray diffraction method. Data Brief 2021; 38:107341. [PMID: 34541264 PMCID: PMC8437781 DOI: 10.1016/j.dib.2021.107341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/30/2022] Open
Abstract
In this paper, we presented the dataset values of full width at half maximum (FWHM) with errors at each point corresponding to the value of longitudinal and transverse residual stress along the three lines for 14 points measured in the EBW welded joints (S960QL and S960M) of the related article [1]. This dataset is used to plot figures and describes their correspondence points with the interrelation of the residual stress graphs (Fig. 4) of the article [1]. The shape of the diffracted peak can be characterised in a simple way by the FWHM, which is the width in degree at half the peak height after background extraction. The measured width consist of instrumental and metallurgical broadening. The variation or increase in FWHM is resulted from the crystalline lattice defect e.g. solute foreign atoms, dislocations and grain boundary. Conversely, if we can determine the physical broadening, we get more information about the structure of the investigated material. In addition, the optical microscopic image of the base materials and weld microstructure are the other parts of the data. Diffraction data were collected using centreless X-ray diffraction (XRD) during in situ residual stress measurement of high strength structural steels S960QL and S960M. A more detailed interpretation of the data presented in this article is provided in article [1]. The presented data are produced as part of the main work entitled "Comparative evaluation of residual stresses in vacuum electron beam welded high strength steel S960QL and S960M butt joints [1]".
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Affiliation(s)
| | - Marcell Gáspár
- Institute of Materials Science and Technology, University of Miskolc, Miskolc, 3515, Hungary
| | - Máté Sepsi
- Institute of Physical Metallurgy, Metal forming and Nanotechnology, University of Miskolc, Miskolc, 3515, Hungary
| | - Valéria Mertinger
- Institute of Physical Metallurgy, Metal forming and Nanotechnology, University of Miskolc, Miskolc, 3515, Hungary
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Rodrigues CS, Dhital S, Kim J, May LG, Wolff MS, Zhang Y. Residual stresses explaining clinical fractures of bilayer zirconia and lithium disilicate crowns: A VFEM study. Dent Mater 2021; 37:1655-1666. [PMID: 34481666 DOI: 10.1016/j.dental.2021.08.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To understand the stress development in porcelain-veneered zirconia (PVZ) and porcelain-veneered lithium disilicate (PVLD) crowns with different veneer/core thickness ratios and cooling rates. To provide design guidelines for better performing bilayer restorations with the aid of Viscoelastic Finite Element Method (VFEM). METHODS The VFEM was validated by comparing the predicted residual stresses with experimental measurements. Then, the model was used to predict transient and residual stresses in the two bilayer systems. Models with two different veneer/core thickness ratios were prepared (2:1 and 1:1) and two cooling protocols were simulated (Fast: ∼300 °C/min, Slow: ∼30 °C/min) using the heat transfer module, followed by stress analysis in ABAQUS. The physical properties of zirconia, lithium disilicate, and the porcelains used for the simulations were determined as a function of temperature. RESULTS PVLD showed lower residual stresses than PVZ. The maximum tensile stresses in PVZ were observed in the cusp area, whereas those in PVLD were located in the central fossa. The 1:1 thickness ratio decreased stresses in both layers of PVZ. Slow cooling slightly decreased residual stresses in both systems. However, the cooling rate effect was more evident in transient stresses. SIGNIFICANCE Slow cooling is preferable for both systems. A thinner porcelain layer over zirconia lowers stresses throughout the restoration. The different stress distributions between PVZ and PVLD may affect their failure modes. Smaller mismatches in modulus, CTE, and specific heat between the constituents, and the use of low Tg porcelains can effectively reduce the deleterious transient and residual tensile stresses in bilayer restorations.
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Affiliation(s)
- Camila S Rodrigues
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University, 777 Eng. Francisco José Longo Av, 12245-000, São José dos Campos, SP, Brazil
| | - Sukirti Dhital
- Department of Civil and Environmental Engineering, University of Connecticut, 261 Glenbrook Rd., U-3037, Storrs, CT 06269, USA
| | - Jeongho Kim
- Department of Civil and Environmental Engineering, University of Connecticut, 261 Glenbrook Rd., U-3037, Storrs, CT 06269, USA
| | - Liliana Gressler May
- Department of Restorative Dentistry, School of Dentistry, Federal University of Santa Maria, 1000 Roraima Av., T Street, Building 26F, 97105-900, Santa Maria, RS, Brazil
| | - Mark S Wolff
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA 19104, USA
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine, University of Pennsylvania, 240 S. 40th Street, Philadelphia, PA 19104, USA.
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Zhan Y, Xu H, Du W, Liu C. Research on the influence of heat treatment on residual stress of TC4 alloy produced by laser additive manufacturing based on laser ultrasonic technique. Ultrasonics 2021; 115:106466. [PMID: 34020226 DOI: 10.1016/j.ultras.2021.106466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/24/2021] [Accepted: 05/09/2021] [Indexed: 06/12/2023]
Abstract
During the laser additive manufacturing (LAM) process large temperature gradients can lead to high level of residual stress. The residual stress can have irreversible effects such as warping and cracking of parts during and post manufacturing. Heat treatment is an effective method to control and eliminate residual stress. In this paper, the TC4 parts are prepared by laser additive manufacturing, and the influence of heat treatment process on residual stress is researched. Laser ultrasonic technology, as an advanced nondestructive testing method, is applied to measure the residual stress under different heat treatment processes for the first time. The surface wave generated by laser is used to evaluate the residual stress. The results show that laser ultrasonic method can complete the in-situ evaluation of residual stress in additive manufacturing components. The residual stress in TC4 deposited specimen is large, the longitudinal stress is obviously greater than the transverse stress, and the maximum residual stress is about half of the yield strength. The residual stress increases gradually from the upper surface to the bottom layer near the substrate before heat treatment. After heat treatment, the residual stress is reduced to low stress level and a small compressive stress appears. The cooling rate and solution temperature are the main factors affecting the residual stress, and the residual stress increases with the increase of cooling rate and solution temperature. The effect of aging temperature and aging time on residual stress is not obvious. The study serves as useful guidelines for engineers to assessment and regulation of residual stress reasonably in LAM.
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Affiliation(s)
- Yu Zhan
- College of Sciences, Northeastern University, Shenyang 110819, China.
| | - Hexuan Xu
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Wenqiang Du
- College of Sciences, Northeastern University, Shenyang 110819, China
| | - Changsheng Liu
- Key Laboratory for Anisotropy and Texture of Materials Ministry of Education, Northeastern University, Shenyang 110819, China
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Huang R, Ogden RW, Penta R. Mathematical Modelling of Residual-Stress Based Volumetric Growth in Soft Matter. J Elast 2021; 145:223-241. [PMID: 34720362 PMCID: PMC8550432 DOI: 10.1007/s10659-021-09834-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 04/08/2021] [Indexed: 05/29/2023]
Abstract
Growth in nature is associated with the development of residual stresses and is in general heterogeneous and anisotropic at all scales. Residual stress in an unloaded configuration of a growing material provides direct evidence of the mechanical regulation of heterogeneity and anisotropy of growth. The present study explores a model of stress-mediated growth based on the unloaded configuration that considers either the residual stress or the deformation gradient relative to the unloaded configuration as a growth variable. This makes it possible to analyze stress-mediated growth without the need to invoke the existence of a fictitious stress-free grown configuration. Furthermore, applications based on the proposed theoretical framework relate directly to practical experimental scenarios involving the "opening-angle" in arteries as a measure of residual stress. An initial illustration of the theory is then provided by considering the growth of a spherically symmetric thick-walled shell subjected to the incompressibility constraint.
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Affiliation(s)
- Ruoyu Huang
- Lightweight Manufacturing Centre, University of Strathclyde, Renfrew, PA4 8DJ UK
| | - Raymond W. Ogden
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ UK
| | - Raimondo Penta
- School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QQ UK
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Pei N, Zhao B, Zhao X, Liu Z, Bond LJ. Analysis of the directivity of Longitudinal Critically Refracted (LCR) waves. Ultrasonics 2021; 113:106359. [PMID: 33540234 DOI: 10.1016/j.ultras.2021.106359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/22/2020] [Accepted: 01/09/2021] [Indexed: 06/12/2023]
Abstract
The use of ultrasonic longitudinal critically refracted (LCR) waves is one approach used for near surface material characterization. It has been shown to be sensitive to stress and, in general, less sensitive to the effects of the texture of the material. Although the LCR wave is increasingly widely applied, in experiments the factors that influence the formation of the LCR beam are seldom discussed. This paper reports a new numerical model used to investigate the transducers' parameters that can contribute to the directionality of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal experimental method is used to study the sensitivity to the transducer parameters which influence the LCR wave beam characteristics. This method provides a design tool used to study and optimize multiple parameter experiments and it can identify which parameter or parameters are of most significance. The effects of incident angle, the aperture and the center frequency of the transducer were all studied. It is shown that the aperture of the transducer, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields. The model was validated by comparision of data to those obtained with a finite element model. Experiments were also performed to confirm the numerical results. The model and experimental data provided improve understanding of the transducer selection and positioning in the optimization of LCR wave fields in experiments, which can be used to give signals which exhibit higher sensitivity for near-surface stress characterization.
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Affiliation(s)
- Ning Pei
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100124, China
| | - Bin Zhao
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100124, China
| | - Xin Zhao
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100124, China
| | - Zenghua Liu
- College of Mechanical Engineering and Applied Electronics Technology, Beijing University of Technology, Beijing 100124, China
| | - Leonard J Bond
- Department of Aerospace Engineering & Center for Nondestructive Evaluation, Iowa State University, Ames, IA 50010, USA.
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Liu Z, Lin B, Liang X, Du A. Inversion of surface damage and residual stress in ground silicon wafers by laser surface acoustic wave technology. Ultrasonics 2021; 113:106367. [PMID: 33550086 DOI: 10.1016/j.ultras.2021.106367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 12/23/2020] [Accepted: 01/20/2021] [Indexed: 06/12/2023]
Abstract
The paper presents a study of surface acoustic waves propagation in a damage layer with finite thickness and residual stress on an orthotropic semi-infinite medium to reveal the application of laser ultrasound in the surface inspection of ground silicon wafers. Biot's theory of small deformations influenced by initial stress forms the basis for this study. Considering the case that the displacement and boundary forces are continuous at the interface and the forces vanish on the free surface, the required dispersion relation is obtained. We consider a sample of (100) silicon wafer by grinding with fine abrasive grains, which has a machined face with a micrometer-level thickness of surface damage and residual stress. In order to discuss the impact of propagation directions, degree of surface damage, residual compressive stress on the velocity characteristics of surface waves, the numerical computation of the dispersion equations is performed. It has been found that surface damage has a significant effect on the dispersion curve, while the residual compressive stress can only cause a small decrease Δc in the surface wave velocity. The velocity decrease Δc becomes obvious at high frequencies. For a fixed residual compressive stress and frequency, Δc hardly changes with the degree of surface damage and propagation directions. Based on the above characteristics, we study the inverse problem on detecting both surface damage and residual stress simultaneously by SAW velocities and give a corresponding iterative algorithm. This study may provide theoretical guidance for non-destructive testing of residual stress.
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Affiliation(s)
- Zaiwei Liu
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300354, China
| | - Bin Lin
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300354, China.
| | - Xiaohu Liang
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300354, China
| | - Anyao Du
- Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300354, China
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Chae H, Huang EW, Woo W, Kang SH, Jain J, An K, Lee SY. Unravelling thermal history during additive manufacturing of martensitic stainless steel. J Alloys Compd 2021; 857:157555. [PMID: 33071463 PMCID: PMC7550262 DOI: 10.1016/j.jallcom.2020.157555] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 06/01/2023]
Abstract
In-situ thermal cycling neutron diffraction experiments were employed to unravel the effect of thermal history on the evolution of phase stability and internal stresses during the additive manufacturing (AM) process. While the fully-reversible martensite-austenite phase transformation was observed in the earlier thermal cycles where heating temperatures were higher than Af, the subsequent damped thermal cycles exhibited irreversible phase transformation forming reverted austenite. With increasing number of thermal cycles, the thermal stability of the retained austenite increased, which decreased the coefficient of thermal expansion. However, martensite revealed higher compressive residual stresses and lower dislocation density, indicating inhomogeneous distributions of the residual stresses and microstructures on the inside and on the surface of the AM component. The compressive residual stresses that acted on the martensite resulted preferentially from transformation strain and additionally from thermal misfit strain, and the decrease in the dislocation density might have been due to the strong recovery effect near the Ac1 temperature.
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Affiliation(s)
- Hobyung Chae
- Department of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - E-Wen Huang
- Department of Materials Science and Engineering, National Chiao Tung University, Hsinchu, 30010, Taiwan
| | - Wanchuck Woo
- Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea
| | - Suk Hoon Kang
- Korea Atomic Energy Research Institute, Daejeon, 34057, Republic of Korea
| | - Jayant Jain
- Department of Materials Science and Engineering, Indian Institute of Technology, New Delhi, 110016, India
| | - Ke An
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, 37831, USA
| | - Soo Yeol Lee
- Department of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Republic of Korea
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Herbster M, Harnisch K, Haberland E, Kriegel P, Döbberthin C, Heyn A, Döring J, Lohmann CH, Bertrand J, Halle T. Effect of deep rolling on subsurface conditions of CoCr28Mo6 wrought alloy to improve the wear resistance of endoprostheses. J Mech Behav Biomed Mater 2021; 118:104398. [PMID: 33667927 DOI: 10.1016/j.jmbbm.2021.104398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/06/2021] [Accepted: 02/11/2021] [Indexed: 12/28/2022]
Abstract
Wear of orthopaedic endoprostheses is associated with adverse local and systemic reactions and can lead to early implant failure. Manufacturing determines the initial subsurface microstructure of an alloy that influences the implant's wear behaviour. Therefore, this study aims at generating enhanced wear resistances by a modification of the surface and subsurface microstructure of a CoCr28Mo6 wrought alloy by applying deep rolling. The state of the art was investigated by means of eleven retrieved CoCr28Mo6 hip implant components from different manufacturers with respect to their subsurface microstructure and micro hardness profiles. CoCr28Mo6 wrought alloy samples (DIN EN ISO 5832-12) were aged at 750 °C for 24 h and/or plastically deformed by deep rolling with varying axial forces (170 N, 230 N and 250 N). The samples were metallographically prepared and investigated using optical and scanning electron microscopy with EDS and EBSD, micro hardness testing, XRD and tribological testing. The retrieved implant components revealed that, independent of the manufacturer, neither the head nor the stem trunnion exhibited a defined subsurface condition. The dominant phase within the implants was face-centered cubic (fcc). Some implants exhibited single hexagonal close-packed (hcp) grains due to a stress-induced phase transformation. The initial CoCr28Mo6 wrought alloy had a fcc crystal structure. After isothermal aging, the matrix entirely transformed to a hcp structure. In the initial fcc-condition, deep rolling generated a plastically deformed surface layer within the first 100 μm and stress-induced phase transformation to hcp was observed. Micro hardness gradients were present in the subsurface of up to 600 μm depth and exhibited a maximum increase of 34% by deep rolling in comparison to the initial fcc-matrix. This trend was confirmed by a correlated increase in residual compressive stresses. In tribological tests under serum lubrication, the modified samples generated lower wear in comparison to the contemporarily used fcc-matrix samples. This study demonstrates that deep rolling is an effective processing to modify the subsurface of a biomedical CoCr28Mo6 wrought alloy in order to increase the wear resistance. The intentional transformation from the fcc to the hcp phase induced by deformation offers great potential for implant application.
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Khajehzadeh M, Boostanipour O, Reza Razfar M. Finite element simulation and experimental investigation of residual stresses in ultrasonic assisted turning. Ultrasonics 2020; 108:106208. [PMID: 32563716 DOI: 10.1016/j.ultras.2020.106208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 02/25/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
The residual stresses in the machined workpiece are of great importance due to their influence on the workpiece fatigue life, as well as its dimensional and geometric accuracy. The metal cutting process has always been accompanied by heat generation and severe plastic deformation. This thermo mechanical loading along with the resulted metallurgical changes are the main sources of residual stresses generation at the surface of machined workpiece. The Ultrasonic Assisted Turning (UAT) reduces the temperature in the cutting region and reduces the average machining forces due to the discontinuous contact of the tool and the workpiece. Reducing the intensity of thermo mechanical loading in the UAT process will affect the residual stresses caused by machining. In this paper, the results of thermo mechanical finite element simulation and experimental studies of residual stresses during UAT of AISI 4140 has been studied. The results of this simulation make it possible to determine the effect of vibration and machining parameters (cutting speed and feed rate) on the magnitude and type of surface residual stresses in the workpiece machined by UAT. Finally, the simulation results are compared with experimental measurements of residual stresses using X-ray diffraction technique. Based on the obtained results, the hoop component of the residual stresses in case of UAT became more compressive averagely by about 73.34% compared to the traditional turning; for instance at constant feed of 0.11 mm/rev and cutting speed of 0.261 m/s, for three different vibration amplitudes of 4, 8 and 12 µm, the machining induced residual stresses became more compressive respectively by 53.34%, 73.00% and 100%.
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Affiliation(s)
- Mohsen Khajehzadeh
- Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran.
| | - Omid Boostanipour
- Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - Mohammad Reza Razfar
- Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran
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Wu J, Augustin CM, Shadden SC. Reconstructing vascular homeostasis by growth-based prestretch and optimal fiber deposition. J Mech Behav Biomed Mater 2020; 114:104161. [PMID: 33229142 DOI: 10.1016/j.jmbbm.2020.104161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/28/2020] [Accepted: 10/23/2020] [Indexed: 12/13/2022]
Abstract
Computational modeling of cardiovascular biomechanics should generally start from a homeostatic state. This is particularly relevant for image-based modeling, where the reference configuration is the loaded in vivo state obtained from imaging. This state includes residual stress of the vascular constituents, as well as anisotropy from the spatially varying orientation of collagen and smooth muscle fibers. Estimation of the residual stress and fiber orientation fields is a formidable challenge in realistic applications. To help address this challenge, we herein develop a growth based Algorithm to recover a residual stress distribution in vascular domains such that the stress state in the loaded configuration is equal to a prescribed homeostatic stress distribution at physiologic pressure. A stress-driven fiber deposition process is included in the framework, which defines the distribution of the fiber alignments in the vascular homeostatic state based on a minimization procedure. Numerical simulations are conducted to test this two-stage homeostasis generation algorithm in both idealized and non-idealized geometries, yielding results that agree favorably with prior numerical and experimental data.
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Affiliation(s)
- Jiacheng Wu
- Department of Mechanical Engineering, University of California, Berkeley, USA
| | - Christoph M Augustin
- Department of Mechanical Engineering, University of California, Berkeley, USA; Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Shawn C Shadden
- Department of Mechanical Engineering, University of California, Berkeley, USA.
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Abstract
PURPOSE Residual stress tensor has an essential influence on the mechanical behaviour of soft tissues and can be particularly useful in evaluating growth and remodelling of the heart and arteries. It is currently unclear if one single radial cut using the opening angle method can accurately estimate the residual stress. In many previous models, it has been assumed that a single radial cut can release the residual stress in a ring of the artery or left ventricle. However, experiments by Omens et al. (Biomech Model Mechanobiol 1:267-277, 2003) on mouse hearts, have shown that this is not the case. The aim of this paper is to answer this question using a multiple-cut mathematical model. METHODS In this work, we have developed models of multiple cuts to estimate the residual stress in the left ventricle and compared with the one-cut model. Both two and four-cut models are considered. Given that the collagen fibres are normally coiled in the absence of loading, we use the isotropic part of the Holzapfel-Ogden strain energy function to model the unloaded myocardium. RESULTS The estimated residual hoop stress from our multiple-cut model is around 8 to 9 times greater than that of a single-cut model. Although in principle infinite cuts are required to release the residual stress, we find four cuts seem to be sufficient as the model agrees well with experimental measurements of the myocardial thickness. Indeed, even the two-cut model already gives a reasonable estimate of the maximum residual hoop stress. We show that the results are not significantly different using homogeneous or heterogeneous material models. Finally, we explain that the multiple cuts approach also applies to arteries. CONCLUSION We conclude that both radial and circumferential cuts are required to release the residual stress in the left ventricle; using multiple radial cuts alone is not sufficient. A multiple-cut model gives a marked increase of residual stress in a left ventricle ring compared to that of the commonly used single-cut model.
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Zarandi EP, Lee TL, Skallerud BH. Data on residual stresses of mooring chains measured by neutron diffraction and hole drilling techniques. Data Brief 2020; 30:105587. [PMID: 32368600 DOI: 10.1016/j.dib.2020.105587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 03/30/2020] [Indexed: 11/20/2022] Open
Abstract
Residual stresses in large offshore mooring chains have been measured for the first time and presented in this article. Two chain links with the same size and material, one only subjected to proof load and no cyclic service loads and the other exposed to service loads as well as the proof load, were selected for the experiment. Residual stresses just below the surface were measured using the hole-drilling technique and the neutron diffraction technique was employed for deeper measurements. The data can be used to investigate residual stress redistribution in the chain links because of material removal due to corrosion and cyclic service loads that the chains are exposed to during their service time. Moreover, the data can be used to validate numerical models for predicting residual stresses. A more detailed interpretation of the data presented in this article is provided in "Experimental and numerical study of mooring chain residual stresses and implications for fatigue life" [1].
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Nazari F, Honarpisheh M, Zhao H. The effect of microstructure parameters on the residual stresses in the ultrafine-grained sheets. Micron 2020; 132:102843. [PMID: 32045858 DOI: 10.1016/j.micron.2020.102843] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/02/2020] [Accepted: 02/02/2020] [Indexed: 11/24/2022]
Abstract
In this research, the influence of microstructure parameters on the residual stresses of ultrafine-grained sheets was investigated. For this purpose, the constrained groove pressing (CGP) process was carried out on the copper sheets with 3 mm thickness, and residual stresses of the CGPed sheets was measured using the contour method. Microstructure of the CGPed specimens was evaluated by the optical microscopy, micro x-ray diffraction (micro-XRD), and transmission electron microscopy (TEM) experiments. Microstructure parameters including crystallites size, dislocations density, and lattice strain were calculated using Williamson-Hall and Williamson-Smallman equations, and the calculated results were validated by the TEM images. The influence of these parameters on the residual stresses was investigated by analysis of variance (ANOVA) method, and two approaches were considered in this way. According to the results, the CGP process can create nanostructures in the CGPed sheets, and with increasing number of CGP passes, grains size, crystallites size, lattice strain, and residual stresses decrease, and density of dislocations increases. Microstructure parameters have a significant effect on the macro-residual stresses, and strain is the most effective parameter. Also, in the ultrafine-grained sheets, micro-parameters have an undeniable contribution, which is the same as that of macro-parameters on the macro-residual stresses.
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Yang B, O'Connell GD. Intervertebral disc swelling maintains strain homeostasis throughout the annulus fibrosus: A finite element analysis of healthy and degenerated discs. Acta Biomater 2019; 100:61-74. [PMID: 31568880 DOI: 10.1016/j.actbio.2019.09.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/24/2019] [Accepted: 09/24/2019] [Indexed: 10/25/2022]
Abstract
Tissues in the intervertebral disc have a large capacity to absorb water, partially due to the high glycosaminoglycan (GAG) content, which decreases linearly from the nucleus pulposus (NP) in the center to the outer annulus. Our recent work showed that fiber network and GAG distribution contributes to development of residual stresses and strains that were compressive in the inner annulus to tensile in the outer annulus. GAG loss in the inner annulus, as observed with early to moderate degeneration, reduced swelling capacity and circumferential-direction stress by over 50%. However, our previous model was not capable of evaluating interactions between the NP and annulus fibrosus (AF) during swelling. In this study, we evaluated the effect of degeneration (GAG content or swelling capacity) on residual stress development throughout the disc. Simulations of moderate to severe degeneration showed a 40% decrease in NP swelling capacity, with a 25% decrease in AF and cartilaginous endplate swelling. Together, these changes in tissue swelling resulted in a decrease in NP pressure (healthy = 0.21 MPa; severe degeneration = 0.03 MPa) that was comparable to observations in human discs. There was a 60% decrease in circumferential-direction residual deformations with early degeneration. Radial-direction stretch switched from compressive to tensile with degeneration, which may increase the risk for tears or delamination. Degeneration had a significant impact on residual stress/stretch and fiber stretch in the posterior AF, which is important for understanding herniation risk. In conclusion, degenerative changes in disc geometry and intradiscal deformations was recreated by only altering NP and AF GAG composition. Since most computational models simulate degeneration by altering material stiffness, this work highlights the importance of directly simulating biochemical composition and distribution to study disc biomechanics with degeneration. STATEMENT OF SIGNIFICANCE: Tissues in the intervertebral disc have a large swelling capacity, due to its high glycosaminoglycan content. Our recent work demonstrated the importance of fiber network and glycosaminoglycan distribution residual stresses and strains development. In this study, we evaluated the effect of swelling on intradiscal deformations between the nucleus pulposus and annulus fibrosus. We also investigated the effect of degenerative glycosaminoglycan loss on swelling-based intradiscal deformations of the intact disc and its subcomponents. Decreases in nucleus glycosaminoglycan content resulted in morphological changes observed with degenerated discs and may help to explain mechanisms behind the increases in annular tears and mechanical dysfunction with degeneration.
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Correia AMO, Pereira VEM, Bresciani E, Platt JA, Borges ALS, Caneppele TMF. Influence of cavosurface angle on the stress concentration and gaps formation in class V resin composite restorations. J Mech Behav Biomed Mater 2019; 97:272-7. [PMID: 31136923 DOI: 10.1016/j.jmbbm.2019.05.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 11/23/2022]
Abstract
The study aimed to evaluate the influence of cavosurface angle on stress concentration and gap formation in class V restorations. Cylindrical cavities 3 mm in diameter were prepared in forty-five bovine incisors, changing only the angle of the bur in relation to the flat surface of the tooth. The cavities maintained the same volume (17.67 mm³). The samples were divided according to the cavosurface angle, into three groups (n = 15): 90°, 120°, 135°. After adhesive application (Futurabond U, VOCO), the cavity was filled with bulk placement of a resin composite (GrandioSO, VOCO). The teeth were analyzed with stereomicroscopy. Data of marginal gap formation were statistically analyzed with a one-way analysis of variance (ANOVA) followed by Tukey tests (significance level: α = 0.05). Finite element analysis (FEA) was used to study residual stress in these geometries and to correlate those stresses with experimentally measured gap formation. The elastic modulus and polymerization shrinkage were determined for FEA. Residual shrinkage stresses were expressed in maximum principal stress (MPS). There was a significant difference in the gap formation among the groups (p = 0.001). A significantly lower marginal gap formation was found for 120° and 135° angles, with no significant difference between them. The cavosurface angle at 90° caused substantially higher stresses, in the restoration interface, with greater marginal gap. For the 120° and 135° angles, the stress concentrations were smaller and were located in the dental structure. The cavosurface angle influenced the marginal gap formation and stress concentration.
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Levayer R. Solid stress, competition for space and cancer: The opposing roles of mechanical cell competition in tumour initiation and growth. Semin Cancer Biol 2019; 63:69-80. [PMID: 31077845 PMCID: PMC7221353 DOI: 10.1016/j.semcancer.2019.05.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 04/23/2019] [Accepted: 05/07/2019] [Indexed: 12/24/2022]
Abstract
The regulation of cell growth, cell proliferation and cell death is at the basis of the homeostasis of tissues. While they can be regulated by intrinsic and genetic factors, their response to external signals emanating from the local environment is also essential for tissue homeostasis. Tumour initiation and progression is based on the misregulation of growth, proliferation and death mostly through the accumulation of genetic mutations. Yet, there is an increasing body of evidences showing that tumour microenvironment also has a strong impact on cancer initiation and progression. This includes the mechanical constrains and the compressive forces generated by the resistance of the surrounding tissue/matrix to tumour expansion. Recently, mechanical stress has been proposed to promote competitive interactions between cells through a process called mechanical cell competition. Cell population with a high proliferative rate can compact and eliminate the neighbouring cells which are more sensitive to compaction. While this emerging concept has been recently validated in vivo, the relevance of this process during tumour progression has never been discussed extensively. In this review, I will first describe the phenomenology of mechanical cell competition focusing on the main parameters and the pathways regulating cell elimination. I will then discuss the relevance of mechanical cell competition in tumour initiation and expansion while emphasizing its potential opposing contributions to tumourogenesis.
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Affiliation(s)
- Romain Levayer
- Institut Pasteur, Department of Developmental and Stem Cell Biology, 25 rue du Dr. Roux, 75015 Paris, France.
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Li B, Roper SM, Wang L, Luo X, Hill NA. An incremental deformation model of arterial dissection. J Math Biol 2019; 78:1277-1298. [PMID: 30456652 PMCID: PMC6453878 DOI: 10.1007/s00285-018-1309-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 10/30/2018] [Indexed: 10/27/2022]
Abstract
We develop a mathematical model for a small axisymmetric tear in a residually stressed and axially pre-stretched cylindrical tube. The residual stress is modelled by an opening angle when the load-free tube is sliced along a generator. This has application to the study of an aortic dissection, in which a tear develops in the wall of the artery. The artery is idealised as a single-layer thick-walled axisymmetric hyperelastic tube with collagen fibres using a Holzapfel-Gasser-Ogden strain-energy function, and the tear is treated as an incremental deformation of this tube. The lumen of the cylinder and the interior of the dissection are subject to the same constant (blood) pressure. The equilibrium equations for the incremental deformation are derived from the strain energy function. We develop numerical methods to study the opening of the tear for a range of material parameters and boundary conditions. We find that decreasing the fibre angle, decreasing the axial pre-stretch and increasing the opening angle all tend to widen the dissection, as does an incremental increase in lumen and dissection pressure.
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Affiliation(s)
- Beibei Li
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Steven M. Roper
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - Lei Wang
- Department of Engineering, Durham University, Durham, UK
| | - Xiaoyu Luo
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
| | - N. A. Hill
- School of Mathematics and Statistics, University of Glasgow, Glasgow, UK
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Shi Q, Roux S, Latourte F, Hild F. Estimation of elastic strain by integrated image correlation on electron diffraction patterns. Ultramicroscopy 2019; 199:16-33. [PMID: 30738984 DOI: 10.1016/j.ultramic.2019.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 01/23/2019] [Accepted: 02/02/2019] [Indexed: 11/29/2022]
Abstract
High-angular-resolution electron backscattered diffraction (HR-EBSD) has been developed to study local elastic strains in crystals. An integrated digital image correlation (DIC) procedure for high resolution diffraction patterns, as recently proposed to bypass several problems of the conventional cross-correlation-based algorithm, was implemented. Through two examples of experimental data where the algorithm was used and compared to conventional means, the current paper illustrates the benefits of the integrated DIC method. It is found that both measurement uncertainty and computation time were simultaneously reduced. Moreover, an enhanced robustness was obtained for relatively high misorientations relative to methods based on cross-correlation. Different computing conditions are explored on experimental data. A number of practical usage conditions are proposed to achieve better precision and speed.
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Affiliation(s)
- Qiwei Shi
- Laboratoire de Mécanique et Technologie (LMT), ENS Paris-Saclay/CNRS/Université Paris-Saclay, 61 Avenue du Président Wilson, Cachan 94235, France; EDF R&D, Site des Renardières, Avenue des Renardières, Ecuelles, Moret-sur-Loing 77818, France.
| | - Stéphane Roux
- Laboratoire de Mécanique et Technologie (LMT), ENS Paris-Saclay/CNRS/Université Paris-Saclay, 61 Avenue du Président Wilson, Cachan 94235, France
| | - Félix Latourte
- EDF R&D, Site des Renardières, Avenue des Renardières, Ecuelles, Moret-sur-Loing 77818, France
| | - François Hild
- Laboratoire de Mécanique et Technologie (LMT), ENS Paris-Saclay/CNRS/Université Paris-Saclay, 61 Avenue du Président Wilson, Cachan 94235, France
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Liu H, Zhang M, Liu M, Martin C, Cai Z, Sun W. Finite element simulation of three dimensional residual stress in the aortic wall using an anisotropic tissue growth model. J Mech Behav Biomed Mater 2019; 92:188-96. [PMID: 30738379 DOI: 10.1016/j.jmbbm.2019.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/16/2018] [Accepted: 01/09/2019] [Indexed: 11/19/2022]
Abstract
Residual stress is believed to play a significant role in the in vivo stress state of the arterial wall, but quantifying residual stress in vivo is challenging. Based on the well-known assumptions that residual stress is a result of heterogeneous arterial growth and that it homogenizes the transmural distribution of arterial wall stress, we propose a new anisotropic tissue growth model for the aorta to recover the three-dimensional residual stress field in a bi-layer human aortic wall. Finite element simulations showed that the predicted residual stress magnitude with this method are within the documented range for human aorta. Particularly, the homeostatic inter-layer stress difference is identified as a key parameter to quantify the opening angle. To the authors' knowledge, this is the first finite element study employing anisotropic growth of aortic tissue in a bi-layer model to generate three-dimensional residual stress field, and the resultant opening angle can match with the experiments. A parametric study found that inter-layer stress homogeneity, arterial blood pressure, axial pre-stretch, and material stiffness strongly affect the residual stress field.
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Song C, Du L, Ji X. Reducing the residual stress in micro electroforming layer by megasonic agitation. Ultrason Sonochem 2018; 49:233-240. [PMID: 30139636 DOI: 10.1016/j.ultsonch.2018.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 08/03/2018] [Accepted: 08/10/2018] [Indexed: 06/08/2023]
Abstract
In order to reduce the large residual stress in micro elelctroforming layer, megasonic assisted electroforming is proposed here. Micro electroforming experiments were performed with and without megasonic agitation, respectively. Four different megasonic power densities were applied to investigate the influence of megasonic agitation on reducing the residual stress. The residual stress was measured by X-ray diffraction (XRD) method. Experiment results show that the residual stresses fabricated with megasonic agitation are less than that fabricated without megasonic. When the megasonic power density is 2 W/cm2, the residual stress can be the minimum value of -125.7 MPa, reduced by 60% in comparison with the value of -315.1 MPa electroformed without megasonic agitation. For exploring the mechanism of megasonic agitation on reducing the residual stress, the dislocation density and crystal orientation were calculated by the single-line Voigt profile analysis and Relative Texture Coefficient (RTC) method, respectively. The diameters and distributions of pits on the surface of electroforming layer were observed by the STM-6 tool microscope and counted by the Image-Pro Plus software. It reveals that one hand of the mechanism is the acoustic streaming produced by megasonic can strengthen the motion of dislocation in crystal lattice and makes the crystal lattices grow towards the equilibrium shape, which is benefit to crystallization with low residual stress. When the megasonic power density is 2 W/cm2, the dislocation density increases to be the maximum value of 8.09 × 1015 m-2 and the difference between RTC(1 1 1) and RTC(2 0 0) decreases to be zero, which is consistent with the residual stress results. The other hand is that the stable cavitation produced by megasonic can provide residual stress release points during the electroforming process.
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Affiliation(s)
- Chang Song
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China
| | - Liqun Du
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China; Key Laboratory for Micro/Nano Technology and System of Liaoning Province, Dalian University of Technology, Dalian 116024, China.
| | - Xuechao Ji
- Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China
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Liu M, Liang L, Liu H, Zhang M, Martin C, Sun W. On the computation of in vivo transmural mean stress of patient-specific aortic wall. Biomech Model Mechanobiol 2018; 18:387-398. [PMID: 30413984 DOI: 10.1007/s10237-018-1089-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 10/24/2018] [Indexed: 11/29/2022]
Abstract
It is well known that residual deformations/stresses alter the mechanical behavior of arteries, e.g., the pressure-diameter curves. In an effort to enable personalized analysis of the aortic wall stress, approaches have been developed to incorporate experimentally derived residual deformations into in vivo loaded geometries in finite element simulations using thick-walled models. Solid elements are typically used to account for "bending-like" residual deformations. Yet, the difficulty in obtaining patient-specific residual deformations and material properties has become one of the biggest challenges of these thick-walled models. In thin-walled models, fortunately, static determinacy offers an appealing prospect that allows for the calculation of the thin-walled membrane stress without patient-specific material properties. The membrane stress can be computed using forward analysis by enforcing an extremely stiff material property as penalty treatment, which is referred to as the forward penalty approach. However, thin-walled membrane elements, which have zero bending stiffness, are incompatible with the residual deformations, and therefore, it is often stated as a limitation of thin-walled models. In this paper, by comparing the predicted stresses from thin-walled models and thick-walled models, we demonstrate that the transmural mean stress is approximately the same for the two models and can be readily obtained from in vivo clinical images without knowing the patient-specific material properties and residual deformations. Computation of patient-specific mean stress can be greatly simplified by using the forward penalty approach, which may be clinically valuable.
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Affiliation(s)
- Minliang Liu
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Liang Liang
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Haofei Liu
- Department of Mechanics, Tianjin University, 92 Weijin Road, Tianjin, 300072, China
| | - Ming Zhang
- Department of Mechanics, Tianjin University, 92 Weijin Road, Tianjin, 300072, China
| | - Caitlin Martin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206, 387 Technology Circle, Atlanta, GA, 30313-2412, USA
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Technology Enterprise Park, Room 206, 387 Technology Circle, Atlanta, GA, 30313-2412, USA.
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Sommer G, Benedikt C, Niestrawska JA, Hohenberger G, Viertler C, Regitnig P, Cohnert TU, Holzapfel GA. Mechanical response of human subclavian and iliac arteries to extension, inflation and torsion. Acta Biomater 2018; 75:235-252. [PMID: 29859367 DOI: 10.1016/j.actbio.2018.05.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/08/2018] [Accepted: 05/25/2018] [Indexed: 11/30/2022]
Abstract
Peripheral vascular trauma due to injuries of the upper and lower limbs are life-threatening, and their treatment require rapid diagnosis and highly-qualified surgical procedures. Experienced surgeons have recognized that subclavian arteries, affected by injuries of the upper limbs, require a more careful handling due to fragility than common iliac arteries, which are may be affected by injures of the lower limbs. We investigated these two artery types with comparable diameter to evaluate the differences in the biomechanical properties between subclavian and iliac arteries. Human subclavian and common iliac arteries of 14 donors either from the right or the left side (age: 63 yrs, SD: 19,9 female and 5 male) were investigated. Extension-inflation-torsion experiments at different axial strains (0-20%), transmural pressures (0-200 mmHg) and torsion (±25°) on preconditioned arterial tubes were performed. Residual stresses in both circumferential and axial direction were determined. Additionally, the microstructure of the tissues was determined via second-harmonic generation imaging and by histological investigations. At physiological conditions (pi=13.3 kPa, λz=1.1) common iliac arteries revealed higher Cauchy stresses in circumferential and axial directions but a more compliant response in the circumferential direction than subclavian arteries. Both arteries showed distinct stiffer behavior in circumferential than in axial direction. Circumferential stiffness of common iliac arteries at physiological conditions increased significantly with aging (r=-0.67,p=0.02). The median inversion stretches, where the axial force is basically independent of the transmural pressure, were determined to be 1.05 for subclavian arteries and 1.11 for common iliac arteries. Both arteries exhibited increased torsional stiffness, when either axial prestretch or inflation pressure was increased. Residual stresses in the circumferential direction were significantly lower for subclavian arteries than for common iliac arteries at measurements after 30 min (p=0.05) and 16hrs (p=0.01). Investigations of the collagen microstructure revealed different collagen fiber orientations and dispersions in subclavian and iliac arteries. The difference in the collagen microstructure revealed further that the adventitia seems to contribute significantly to the passive mechanical response of the tested arteries at physiological loadings. Histological investigations indicated pronounced thickened intimal layers in subclavian and common iliac arteries, with a thickness comparable to the adventitial layer. In conclusion, we obtained biomechanical differences between subclavian and common iliac arteries, which possibly resulted from their different mechanical loadings/environments and respective in vivo movements caused by their anatomical locations. The biomechanical differences explored in this study are well reflected by the microstructure of the collagen and the histology of the investigated arteries, and the results can improve trauma patient care and endovascular implant design. STATEMENT OF SIGNIFICANCE During surgical interventions surgeons experienced that subclavian arteries (SAs) supplying the upper extremities, appear more fragile and prone to damage during surgical repair than common iliac arteries (CIAs), supplying the lower extremities. To investigate this difference in a systematic way the aim of this study was to compare the biomechanical properties of these two arteries from the same donors in terms of geometry, extension-inflation-torsion behavior, residual stresses, microstructure, and histology. In regard to cardiovascular medicine the material behavior of aged human arteries is of crucial interest. Moreover, the investigation of SA is important as it can help to improve surgical procedures at this challenging location. Over the long-term it might well be of value in the construction of artificial arteries for substituting native arteries. In addition, the analysis of mechanical stresses can improve design and material choice for endovascular implants to optimize long-term implant function.
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Affiliation(s)
- Gerhard Sommer
- Institute of Biomechanics, Graz University of Technology, Austria
| | | | | | - Gloria Hohenberger
- Department of Orthopedics and Trauma Surgery, Medical University Graz, Austria
| | | | - Peter Regitnig
- Institute of Pathology, Medical University Graz, Austria
| | - Tina U Cohnert
- Clinical Department of Vascular Surgery, Medical University Graz, Austria
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Austria; Faculty of Engineering Science and Technology, Norwegian University of Science and Technology, Trondheim, Norway.
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Fardin VP, Bonfante EA, Coelho PG, Janal MN, Tovar N, Witek L, Bordin D, Bonfante G. Residual stress of porcelain-fused to zirconia 3-unit fixed dental prostheses measured by nanoindentation. Dent Mater 2017; 34:260-271. [PMID: 29258696 DOI: 10.1016/j.dental.2017.11.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/12/2017] [Accepted: 11/09/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To evaluate the residual stress (nanoindentation based on hardness) of fatigued porcelain-fused to zirconia 3-unit fixed dental prostheses (FDP) with different framework designs. METHODS Twenty maxillary 3-unit FDP replacing second-premolar (pontic) were fabricated with conventional framework-design (even-thickness of 0.5mm and 9mm2 connector area) and modified framework-design (thickness of 0.5mm presenting lingual collar connected to proximal struts and 12mm2 connector area). Connector marginal ridges were loaded and the fractured and suspended FDPs were divided (n=3/each) into: (1) Fractured zirconia even-thickness (ZrEvenF); (2) Suspended zirconia even-thickness (ZrEvenS); (3) Fractured zirconia with modified framework (ZrModF); (4) Suspended zirconia with modified framework (ZrModS); (5) Non-fatigued FDP with conventional framework design (Control). The FDPs were nanoindented at 0.03mm (Region of Interest (ROI) 1), 0.35mm (ROI 2) and 1.05mm (ROI 3) distances from porcelain veneer outer surface with peak load 4000μN. The Linear Mixed Analysis of Variance (ANOVA) Model on ranks and Least Significant Difference Test on ranks (95%) were used. RESULTS Highest rank hardness values were found for Control group and ZrModS, whereas the lowest values were found in ZrModF. Statistical differences (p=0.000) were found among all groups except for comparison between ZrModS and Control group (p=0.371). Hardness between ROIs were statistically significant different (p<0.001) where ROI 1 presented the lowest values. SIGNIFICANCE Framework-design modification did not influence the residual stress of porcelain-fused to zirconia fatigued 3-unit FDP. Whereas fractured FDPs showed the highest residual stress compared to suspended and control FDPs. Residual stress increased as nanoindented away from framework.
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Affiliation(s)
- Vinicius P Fardin
- Department of Prosthodontics, University of Vila Velha, Vila Velha, ES, Brazil; Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil.
| | - Estevam A Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
| | - Paulo G Coelho
- Department of Biomaterials and Biomimetics, New York University, New York, NY, USA; Hansjörg Wyss Department of Plastic Surgery, NYU Langone Medical Center, New York, NY, USA
| | - Malvin N Janal
- Department of Epidemiology and Health Promotion, New York University College of Dentistry, New York, NY, USA
| | - Nick Tovar
- Department of Biomaterials and Biomimetics, New York University, New York, NY, USA
| | - Lukasz Witek
- Department of Biomaterials and Biomimetics, New York University, New York, NY, USA
| | - Dimorvan Bordin
- Department of Operative Dentistry, Guarulhos University, Guarulhos, SP, Brazil
| | - Gerson Bonfante
- Department of Prosthodontics and Periodontology, University of São Paulo - Bauru School of Dentistry, Bauru, SP, Brazil
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Masoomi M, Shamsaei N, Winholtz RA, Milner JL, Gnäupel-Herold T, Elwany A, Mahmoudi M, Thompson SM. Residual stress measurements via neutron diffraction of additive manufactured stainless steel 17-4 PH. Data Brief 2017; 13:408-14. [PMID: 28664178 DOI: 10.1016/j.dib.2017.06.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/29/2017] [Accepted: 06/13/2017] [Indexed: 11/24/2022] Open
Abstract
Neutron diffraction was employed to measure internal residual stresses at various locations along stainless steel (SS) 17-4 PH specimens additively manufactured via laser-powder bed fusion (L-PBF). Of these specimens, two were rods (diameter=8 mm, length=80 mm) built vertically upward and one a parallelepiped (8×80×9 mm3) built with its longest edge parallel to ground. One rod and the parallelepiped were left in their as-built condition, while the other rod was heat treated. Data presented provide insight into the microstructural characteristics of typical L-PBF SS 17-4 PH specimens and their dependence on build orientation and post-processing procedures such as heat treatment. Data have been deposited in the Data in Brief Dataverse repository (doi:10.7910/DVN/T41S3V).
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Dai D, Gu D, Poprawe R, Xia M. Influence of additive multilayer feature on thermodynamics, stress and microstructure development during laser 3D printing of aluminum-based material. Sci Bull (Beijing) 2017; 62:779-87. [PMID: 36659274 DOI: 10.1016/j.scib.2017.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 04/01/2017] [Accepted: 05/02/2017] [Indexed: 01/21/2023]
Abstract
A transient three dimensional model for describing the temperature behavior, thermo-capillary convection, microstructure evolution and the resultant mechanical properties during selective laser melting of AlN/AlSi10Mg composite is proposed. The powder-solid transformation, temperature dependent physical properties and the preservation of the heat are taken into account. The effect of the additive manufacturing multilayer feature on the molten pool dynamics, cooling rate, crystal size, microstructure morphology, micro-hardness and types of the residual stress has been investigated. It shows that the operating temperature and the thermo-capillary convection obtained within the molten pool generally increases as the processing multilayers are successively added, while the thermal effect depth is negatively reduced. The preferential direction of the heat diffusion generally changes from a downward pattern, then to the slightly strengthened horizontal direction and finally to a typically horizontal one for various deposited layers being processed. Therefore, the microstructure of the solidified part along the building direction (Region I to Region V) undergoes an interesting transformation: directional columnar cellular microstructure, crosswise-extended cellular microstructure, refined cellular microstructure, fragmentation microstructure and the coarse cellular microstructure. The tensile stress and the compressive stress are comprehensively obtained within the finally solidified layers, significantly influencing the micro-hardness.
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